[移动开发]arcgis for android 捕捉顶点

import android.graphics.Color;
import android.os.Bundle;
import android.view.MotionEvent;

import androidx.appcompat.app.AppCompatActivity;

import com.esri.arcgisruntime.geometry.GeometryEngine;
import com.esri.arcgisruntime.geometry.Point;
import com.esri.arcgisruntime.geometry.PointCollection;
import com.esri.arcgisruntime.geometry.Polygon;
import com.esri.arcgisruntime.geometry.ProximityResult;
import com.esri.arcgisruntime.geometry.SpatialReferences;
import com.esri.arcgisruntime.mapping.ArcGISMap;
import com.esri.arcgisruntime.mapping.Basemap;
import com.esri.arcgisruntime.mapping.view.DefaultMapViewOnTouchListener;
import com.esri.arcgisruntime.mapping.view.Graphic;
import com.esri.arcgisruntime.mapping.view.GraphicsOverlay;
import com.esri.arcgisruntime.mapping.view.MapView;
import com.esri.arcgisruntime.symbology.SimpleFillSymbol;
import com.esri.arcgisruntime.symbology.SimpleLineSymbol;
import com.esri.arcgisruntime.symbology.SimpleMarkerSymbol;

import java.util.Arrays;

import butterknife.BindView;
import butterknife.ButterKnife;

public class MainActivity extends AppCompatActivity {
    @BindView(R.id.mapView)
    MapView mapView;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main5);
        ButterKnife.bind(this);

        PointCollection polygonPoints = new PointCollection(SpatialReferences.getWebMercator());
        polygonPoints.addAll(Arrays.asList(
                new Point(-5991501.677830, 5599295.131468),
                new Point(-6928550.398185, 2087936.739807),
                new Point(-3149463.800709, 1840803.011362),
                new Point(-1563689.043184, 3714900.452072),
                new Point(-3180355.516764, 5619889.608838)
        ));

        Polygon polygon = new Polygon(polygonPoints);
        SimpleLineSymbol polygonOutlineSymbol = new SimpleLineSymbol(SimpleLineSymbol.Style.SOLID, Color.GREEN, 2f);
        SimpleFillSymbol polygonFillSymbol =
                new SimpleFillSymbol(SimpleFillSymbol.Style.FORWARD_DIAGONAL, Color.GREEN, polygonOutlineSymbol);
        Graphic polygonGraphic = new Graphic(polygon, polygonFillSymbol);

        // create graphics with symbols for tapped location, nearest coordinate, and nearest vertex
        Graphic tappedLocationGraphic = new Graphic();
        tappedLocationGraphic.setSymbol(new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.X, Color.MAGENTA, 15f));
        Graphic nearestCoordinateGraphic = new Graphic();
        nearestCoordinateGraphic.setSymbol(new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.DIAMOND, Color.RED, 10f));
        Graphic nearestVertexGraphic = new Graphic();
        nearestVertexGraphic.setSymbol(new SimpleMarkerSymbol(SimpleMarkerSymbol.Style.CIRCLE, Color.BLUE, 15f));

        // create a graphics overlay to show the polygon, tapped location, and nearest vertex/coordinate
        GraphicsOverlay graphicsOverlay = new GraphicsOverlay();
        graphicsOverlay.getGraphics().addAll(Arrays.asList(
                polygonGraphic,
                tappedLocationGraphic,
                nearestCoordinateGraphic,
                nearestVertexGraphic
        ));

        // create a map with a basemap and add it to the map view
        ArcGISMap map = new ArcGISMap(Basemap.createTopographic());
        mapView.setMap(map);

        // add the graphics overlay to the map view
        mapView.getGraphicsOverlays().add(graphicsOverlay);

        // zoom to the polygon's extent
        mapView.setViewpointGeometryAsync(polygon.getExtent(), 100.0);

        // get the nearest vertex on tap
        mapView.setOnTouchListener(new DefaultMapViewOnTouchListener(MainActivity5.this, mapView){
            @Override
            public boolean onSingleTapConfirmed(MotionEvent e) {
                // create a screen point from where the user tapped
                android.graphics.Point screenPoint = new android.graphics.Point(Math.round(e.getX()), Math.round(e.getY()));
                // create a map point from the screen point
                Point mapPoint = mapView.screenToLocation(screenPoint);
                // the map point should be normalized to the central meridian when wrapping around a map,
                // so its value stays within the coordinate system of the map view
                Point normalizedMapPoint = (Point) GeometryEngine.normalizeCentralMeridian(mapPoint);
                // show where the user clicked
                tappedLocationGraphic.setGeometry(normalizedMapPoint);

                // use the geometry engine to get the nearest vertex
                ProximityResult nearestVertexResult = GeometryEngine.nearestVertex(polygon, normalizedMapPoint);
                // set the nearest vertex graphic's geometry to the nearest vertex
                nearestVertexGraphic.setGeometry(nearestVertexResult.getCoordinate());
                // use the geometry engine to get the nearest coordinate
                ProximityResult nearestCoordinateResult =
                        GeometryEngine.nearestCoordinate(polygon, normalizedMapPoint);
                // set the nearest coordinate graphic's geometry to the nearest coordinate
                nearestCoordinateGraphic.setGeometry(nearestCoordinateResult.getCoordinate());

                // show the distances to the nearest vertex and nearest coordinate
//                distanceLayout.visibility = VISIBLE
//                val vertexDistance = (nearestVertexResult.distance / 1000.0).toInt()
//                val coordinateDistance = (nearestCoordinateResult.distance / 1000.0).toInt()
//                vertexDistanceTextView.text = getString(R.string.nearest_vertex, vertexDistance)
//                coordinateDistanceTextView.text = getString(R.string.nearest_coordinate, coordinateDistance)
                return true;
            }
        });
    }
}

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <com.esri.arcgisruntime.mapping.view.MapView
        android:id="@+id/mapView"
        android:layout_width="match_parent"
        android:layout_height="match_parent" />

</LinearLayout>